1. Field of the Invention
This invention relates to weighbridges for weighing large loads and supporting systems for such weighbridges, and more particularly, to a weighbridge having an easily assembled pivotal supporting system which also may be used as a connecting system for sections or portions of the weighbridge.
2. Description of the Prior Art
Weighbridges adapted for weighing large loads, such as trucks, are known in the art. Some weighbridges have electronic measuring means, and others use mechanical measuring means. One weighbridge or scale utilizing electronic transducers or load cells is manufactured by UniBridge Scale Systems of Knowles, Okla., and described in a UniBridge brochure entitled "Electronic Truck Scales". This prior electronic weighbridge may include a plurality of deck sections with each deck section interconnected by a pair of connecting modules. Each connecting module includes an electronic transducer supported on a base member having an opening therethrough. The transducer is positioned parallel to the sides of the deck sections, and a pin is disposed through the opening in the base member substantially parallel to the transducer and having ends which extend beyond the ends of the transducer. The pin is hung from the transducer by means of a pair of opposite links, each link supporting one end of the pin and hanging from an extended end of the transducer. A load-bearing saddle member is bolted to each of the deck portions and has opposite sides with downwardly facing grooves therein for engaging, and bearing upon, the opposite extended ends of the pin, such that a load from the deck portions is transmitted to the electronic transducer through the links. This apparatus has worked well, but the modules require significant time for assembly because the loadbbearing members must be bolted to the deck sections. The present invention, which allows pivotal movement between adjacent deck sections on an electronic weighbridge and which requires no bolting to connect the deck sections, offers an improvement over this previously known weighbridge.
The heavy-duty weigh scale of Leiman, disclosed in U.S. Pat. No. 4,549,622, uses a double-ended, shear-beam-type transducer under longitudinally extending beams of the scale. The transducer has opposite fixed ends so that loading on the load cell is at the center thereof through a chair member and a suspension link. Bearing means on the link engages the center of the load cell, and the chair member pivotally rests on cylindrical bearing portions of the link. The chair member is bolted to the scale, in a manner similar to the UniBridge device, and further, the load cell itself is bolted in place and must have the link positioned therearound prior to this bolting. This apparatus is not particularly well suited for interconnecting deck sections of a weighbridge, and unlike the present invention, requires bolting for assembly.
U.S. Pat. No. 4,066,140 to Conley discloses a heavy-duty industrial scale with transducers positioned transversely with respect to longitudinal beams in the scale. As with the Leiman device, the transducer is affixed at its outer ends and has an upper link disposed terearound to bear against the center of the transducer with a bottom link extending downwardly from the upper link and integrally formed therewith. A cross pin rests on the bottom link and opposite legs of a mounting chair rest on outer ends of the cross pin. In an alternate embodiment, the transducer has a cantilevered end. This apparatus has the same limitations as Leiman in that the transducer must be bolted to a support member, and the chair must be attached to the scale. This device, like Leiman, also does not appear to be well adapted for interconnecting two deck sections of a weighbridge.
U.S. Pat. No. 4,627,507 to Powell et al. discloses a load cell fixture similar to that used in the Conley apparatus, but instead uses a pair of links positioned on opposite sides of the load cell with an upper pin resting on the load cell. The links hang from the upper pin and support the lower pin, upon which a mounting chair rests. This device has the same limitations as Leiman and Conley, except that it does not require the positioning of a link around the load cell prior to bolting the load cell to the support member.
As indicated, the present invention provides a supporting and connecting system for sections or portions of an electronic weighbridge. The system is easily assembled because no bolting is required, and further provides for pivotation between adjacent weighbridge sections, thus reducing fatigue and the relatively frequent repair required thereby. The present invention also provides a pivotal supporting system for a mechanical weighbridge which is quickly assembled with no bolting and operates under the same principles as on the electronic weighbridge. This pivotal support system also reduces possibilities of induced moments due to uneven loading. The pivotal support system eliminates uplifting reactions on one weighbridge section from an adjacent weighbridge section due to extreme, uneven loading. This, in turn, improves scale accuracy.